http://www.alphasondesigns.com/produ...atID=56&varID= - really nice brackets this range.
If you went bigger than 26" then yes you might need a bigger bracket, but it does have up to 400x200 mounts, so some 32's may fit.
For simplicity of fixing, use these:
http://www.directbuildingproducts.co...s3.php?id=1525 - I've NEVER had a problem with these fixings - very easy to go in and very very secure. If you call DBP they'll post a few out to you, saving the £9 delivery charge!
HTH
Chris